evolution erectus evolution erectus in Asia. However, the timing of the first appearance of at the site has been et al. controversial. Using a combination of dating techniques for hominin-bearing sediments, Matsu'ura ∼ H. erectus resolved the arrival of at 1.3 million years ago (see the Perspective by Brasseur). This dating suggests that the earliest hominins in Sangiran are at least 200,000 years younger than has been thought and may represent an important step to the resolution of the controversy.

Matsui, H., Jia, J., Tsuji, T., Liang, Y., Masuda, Y., 2020. Microsecond simulation study on the replacement of methane in methane hydrate by carbon dioxide, nitrogen, and carbon dioxide - nitrogen mixtures. Fuel 263, 116640.

http://www.sciencedirect.com/science/article/pii/S0016236119319945 Replacement of methane (CH ) in CH hydrate by carbon dioxide (CO ) can enable recovery of CH , which is a 4 4 2 4 potential future energy resource, while sequestering CO to mitigate the effects of global warming. However, 2 little work has been done to address the effects of impurities on CO replacement, and the detailed mechanisms. 2 Here, microsecond molecular dynamics simulations were performed to understand the influence of nitrogen (N ) gas on the process of replacing CH in CH hydrate with CO at 280 K and 6 MPa. The results show that 2 4 4 2 CO molecules can penetrate more deeply into CH hydrate phase when it is mixed with N . This is mainly 2 4 2 because N can favor the decomposition of CH hydrate and expand the replacement area of CH by guest 2 4 4 molecules. We confirm that the replacement of CH by CO and N preferably occurs in large and small cages, 4 2 2 respectively. In most cases, a mixture hydrate reforms at the outmost layer of the hydrate surface. The CO /N 2 2 mixture shows an overall higher replacement efficiency than pure CO case. Our work demonstrates that CH 2 4 recovery by CO injection in CH hydrate can be facilitated by N . The penetration depth of replacement is 2 4 2 sensitive to the ratio of N to CO . The knowledge obtained in this study will be helpful for the effective 2 2 utilization of CO /N mixtures to maximize the recovery percentage of CH from hydrate. 2 2 4

Maus, D., Heinz, J., Schirmack, J., Airo, A., Kounaves, S.P., Wagner, D., Schulze-Makuch, D., 2020. Methanogenic Archaea can produce methane in deliquescence-driven Mars analog environments. Scientific Reports 10, 6.

https://doi.org/10.1038/s41598-019-56267-4 The current understanding of the Martian surface indicates that briny environments at the near-surface are temporarily possible, e.g. in the case of the presumably deliquescence-driven Recurring Slope Lineae (RSL). However, whether such dynamic environments are habitable for terrestrial organisms remains poorly understood. This hypothesis was tested by developing a Closed Deliquescence System (CDS) consisting of a mixture of desiccated Martian Regolith Analog (MRA) substrate, salts, and microbial cells, which over the course of days became wetted through deliquescence. The methane produced via metabolic activity for three Methanosarcina mazei M. barkeri M. soligelidi methanogenic archaea: , and , was measured after exposing them to three different MRAsubstrates using either NaCl or NaClO as a hygroscopic salt. Our experiments showed 4 M. soligelidi M. barkeri that (1) rapidly produced methane at 4 °C, (2) produced methane at 28 °C though not at M. mazei 4 °C, (3) was not metabolically reactivated through deliquescence, (4) none of the species produced methane in the presence of perchlorate, and (5) all species were metabolically most active in the phyllosilicate- containing MRA. These results emphasize the importance of the substrate, microbial species, salt, and temperature used in the experiments. Furthermore, we show here for the first time that water provided by deliquescence alone is sufficient to rehydrate methanogenic archaea and to reactivate their metabolism under conditions roughly analogous to the near-subsurface Martian environment.

Mayhew, L.E., Ellison, E.T., 2020. A synthesis and meta-analysis of the Fe chemistry of serpentinites and serpentine minerals. Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 378, 20180420.

https://doi.org/10.1098/rsta.2018.0420